The present invention relates to a connector for connecting tubes, for example a connector for connecting a resin tube and a metal pipe to each other in order to transfer various fluids such as fuel, oil, water or air.
Conventionally, there have been known various connectors for mutually coupling various hoses, pipes and the like of automobiles. FIG. 12 shows one of typical examples. The connector comprises a tubular male member 10 such as a metallic pipe, a cylindrical housing member 20 having a large diameter portion for receiving an end of the male member 10 at one of ends and a tube inserting portion 21 for inserting a resin tube or the like at the other end and an engagement member 25 for being inserted from an opening at one of the ends of the housing member 20 and engaged with the housing member 20 and serving to engage an annular projecting portion 11 of the male member 10 to be coupled to the housing member 20, and furthermore, an annular seal member 12 such as an 0 ring for sealing a portion between the inner periphery of the central part of the housing member 20 and the outer peripheral surface of the male member 10, and an annular bush 13 and a collar 14 which serve to hold the seal member 12 in a predetermined position.
In the connector of this kind, the engagement member 25 is constituted by a deformable portion and a non-deformable portion and elastic deformation can be carried out by cutting out at least one portion in an axial direction. Accordingly, the engagement member 25 is inserted into the housing member 20 with a reduction in a diameter and an engagement portion 26 is snapped into a window portion 22 provided in the housing member 20. In the engagement member 25 engaged with the housing member 20, a non-deformable portion 25a extending diagonally in a radial direction is snapped into an annular projecting portion 11 of the male member 10 through the deformable portion so that the male member 10 can be coupled to the housing member 20. Moreover, a pair of operation arms 27 are provided integrally with one of ends of the engagement member 25. By pushing the operation arm portion 27 inward radially to reduce the whole diameter, the male member 10 can be removed from the engagement member 25 and the housing member 20.
In a connecting structure using the conventional connector, the number of parts is so large that a reduction in a cost is limited and a whole axial length is so great that a reduction in a size is difficult. More specifically, as shown in FIG. 12, it is necessary to receive the almost cylindrical engagement member 25 having the operation arm portion 27 and the bush 13 in the housing member 20 and to engage and connect the annular projecting portion 11 of the male member 10 inserted from the opening at one of the ends of the housing member 20 with the other end of the engagement member 25. Therefore, the whole length of the connector portion in the axial direction is necessarily very great.
Moreover, GB2022727A has disclosed a connection structure in which a male member (fuel injection nozzle) is inserted and fastened into a bore of an inlet portion of a female member through an elastomeric sleeve. The elastomeric sleeve comprises a bead portion including, on one of ends, an outward projecting portion which projects outward radially and an inward projecting portion which projects inward radially, and on the other end, an introducing end portion including a rib projecting inward radially. Furthermore, the male member comprises, on the insertion end, an engaging outer peripheral groove to be engaged with the radial projecting portion and the female member comprises, on the inner peripheral surface of the bore, an annular groove to be engaged with the outward projecting portion. The thickness of the wall of the bead portion in the elastomeric sleeve is slightly greater than that of a clearance formed by the engagement outer peripheral groove and the annular groove. Moreover, the thickness of the rib on the introducing end portion of the elastomeric sleeve is greater than a clearance formed by the male member and the bore corresponding thereto. With the connection structure for the fuel injection nozzle, accordingly, the male member is pressed into the bore of the inlet portion of the female member so that the male member can be fastened into the bore of the inlet portion of the female member through the bead portion of the elastomeric sleeve and can be sealed through the rib formed in the introducing end portion of the elastomeric sleeve.
With such a connection structure, it is necessary to cause the thickness of the bead portion to be much greater than the above stated clearance in order to strongly fasten the male member into the bore of the inlet portion of the female member through the bead portion of the elastomeric sleeve. After the elastomeric sleeve is previously assembled into the engagement outer peripheral groove of the male member, the male member should be inserted into the bore of the inlet portion of the female member and the bead portion of the elastomeric sleeve should be surely engaged so as not to get out of the annular groove. However, it is hard to sense whether both are surely engaged or not. If both are incompletely engaged, both might get out from each other during use and the male member should be inserted by a comparatively strong force. Moreover, it is difficult to easily remove the male member from the female member. Furthermore, the elastomeric sleeve should be assembled into the engagement outer peripheral groove of the male member in advance. For this reason, there is a danger that the exposed elastomeric sleeve might be damaged before the insertion in the female member.
In consideration of the conventional circumstances, it is a first object of the present invention to provide a connector capable of decreasing the number of parts to reduce a cost and to obtain a smaller size in an axial direction, and of preventing a seal member from being damaged, thereby easily and surely connecting a male member to a female member without requiring a great inserting force. Preferably, it is a second object of the present invention to provide a connector capable of easily removing the male member from the female member by means of a release tool.
In order to achieve the above-mentioned objects, the present invention provides a connector in which a tubular male member is fastened together with a tubular female member by a cylindrical elastomeric sleeve held. in a receive bore of a cylindrical receive end portion formed on one end of said tubular female member, characterized in that the tubular male member includes an insert end portion having a cylindrical tip end portion and an annular projecting portion that is located behind and adjacent to the tip end portion, the cylindrical elastomeric sleeve is provided at its one end with a cylindrical swelling portion having an annular engagement inner peripheral groove adapted to receive the annular projecting portion by snapping the annular projecting portion of the male member, and the cylindrical elastomeric sleeve is provided at the other end with a cylindrical seal portion which is adjacent to the swelling portion and which has an inner periphery that liquid-tightly engages an outer peripheral surface of the tip portion of the tubular male member, the tubular female member is provided at its one end of the received end portion with a first diameter portion having a first bore having a larger inner diameter than the outer diameter of the cylindrical seal portion of said elastomeric sleeve for receiving the swelling portion, an entrance of the first diameter portion includes an annular restriction rib that is projected radially inward from an inner peripheral surface of the first diameter portion, the annular restriction rib having an inner diameter slightly larger than an outer diameter of the annular projecting portion of the tubular male member and the annular restriction rib engaging an outer surface of one end of the swelling portion of the cylindrical elastomeric sleeve when a pulling-out force is applied between the tubular male member and the tubular female member, and the receive end portion is provided at the other end with a second diameter portion having a second bore adapted to receive the cylindrical seal portion, and the first bore of the first diameter portion is provided therein with space capable of spreading a diameter of the cylindrical swelling portion of the elastomeric sleeve between the first diameter portion and the swelling portion in order to snap the annular projecting portion of the tubular male member into the engagement inner peripheral groove of the swelling portion.
Moreover, the connector according to the present invention is characterized in that the second diameter portion of the tubular female member includes a step portion for restricting a movement of the cylindrical elastomeric sleeve toward the other end side thereof, and that the tubular female member is integrally formed of a metal tube having a constant thickness and that the annular restriction rib formed on the inlet of the first diameter portion of the tubular female member includes a reinforcing portion extending outward radially.
Furthermore, the connector according to the present invention is characterized in that one end of the engagement inner peripheral groove formed on the swelling portion of the cylindrical elastomeric sleeve includes an annular lock surface that engages with the annular projecting portion of inserted the tubular male member, and in order to form the annular lock surface, one end opening of the cylindrical swelling portion includes a thick walled portion, and an inner peripheral surface of the thick walled portion is formed as a guide surface whose diameter is gradually reduced toward the other end of said engagement inner peripheral groove.
Furthermore, in the connector according to the present invention, the cylindrical elastomeric sleeve is made of material having different characteristic and includes a first region comprising the cylindrical swelling portion and one end of the cylindrical seal portion located adjacent to the swelling portion, and a second region comprising the other end of the cylindrical seal portion located adjacent to one end of the swelling portion, the first and second regions are determined by a different of said material, the first region comprises an elastomer having excellent sealing ability at a low temperature and the second region comprises a low fuel permeable elastomer, or the first region comprises a low fuel permeable elastomer and the second region comprises an elastomer having excellent sealing ability at a low temperature,
Furthermore, in the connector according to the present invention, the elastomer having excellent sealing ability at a low temperature is one of NBR (nitrile rubber), FVMQ (Fluoro silicon rubber)and NBR.PVC (mixture of nitrile rubber and vinyl chloride), and said low fuel permeable elastomer is FKM (Fluoro elastomer) ,and the engagement inner peripheral groove formed on the swelling portion of the elastomeric sleeve may be formed into a channel-like shape.
According to the present invention, in the connection of the female member and the male member, the engagement function for connecting the male member to the female member and the cylindrical elastomeric sleeve attached to and held in the female member and the seal function for the seal member are shared. Consequently, the structure is simplified and the number of parts is decreased so that a cost can be reduced. In addition, the cylindrical elastomeric sleeve has the engagement inner peripheral groove for snapping the annular projecting portion of the male member into one end side, while the receive end portion of the female member has a space capable of increasing the diameter of the swelling portion between the first diameter portion and the swelling portion of the elastomeric sleeve in the first bore. Therefore, when the male member is to be connected to the female member, the annular projecting portion can be fastened easily and reliably into the engagement inner peripheral groove without requiring a strong inserting force.
Furthermore, since the cylindrical elastomeric sleeve in the connector according to the present invention is previously attached to and held in the female member, it is not damaged and a portion between the female member and the male member can be sealed surely. Moreover, the insertion and attachment of the bush and the collar for preventing the movement of the elastomeric sleeve can be omitted. In addition, in the connector according to the present invention, the number of coupling portions of the female member and the male member can be decreased so that reliability for a sealing ability can be enhanced still more. In a preferred embodiment, furthermore, a thick walled portion is provided on the opening at one end of the swelling portion of the cylindrical elastomeric sleeve and the inner peripheral surface of the thick walled portion includes a guide surface having a diameter gradually reduced toward the other end side. Therefore, the male member can be fastened more easily and can be released readily by using a release tool.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.